Everybody loves somebody sometime
Everybody falls in love somehow
Something in your kiss just told me
That sometime is now
- Dean Martin

Today we’re announcing the launch of a brand new dating service… EHarmony!
Whats that? There already is an EHarmony you say? Well you didn’t read the fine print. Welcome to

E_lementalHarmony!

Let me explain how it works. Lonely elements are looking for love and your going to help sign them up for this new dating service. You’ll create an online profile for them, a biography, and then a Video Dating Profile! Soon your element will be sharing their electrons and their lives with that special ion.To the left is an example of Hydrogen’s online dating profile. Directions and the profile template is available below and on the semester 2 docs page.

You will select your Element at Random. Once you have selected your element, add your first and last name in the approproiate row on this spread sheet. ( Element Spread Sheet – Google Doc ) Please do not adjust the names of other people as this document is open to everyone. At the end of the day I will close the document.

When you’re finished you’ll be able to view other element’s profiles and videos… you might even make a special connection that will mean something very special… I’m speaking of course, of BONUS POINTS. Good Luck!

Elemental Online Dating Instructions & Rubric

Online Dating Profile Template

Poll Everywhere Link

Today we’ll be turning in our (gigantic) Limiting Reactants Packet.

Yes, you will have time to complete it in class.

Once you’ve completed your packet, you will be given a copy of the Unit 7 Practice Test. This test will be identical in setup, appearance, and expectation to the real Unit 7 Test on Tuesday March 5th

The answers will be posted today so you can check your work… however, the work will not be posted until Monday so you are not tempted to cheat. YOU MUST SHOW ALL WORK on the practice test and ON THE TEST.

In addition, I have posted information on the Board in Room 4335 (and below) to assist you in determining what information to put where in your table. YOU WILL BE GRADED BASED ON THE INFORMATION YOU PUT IN YOUR TABLE! So it’s important to learn how to discover numbers and where to place them.

Monday, we’ll be reviewing once more and there may even be an opportunity for Extra Credit. So study up and focus on Chem for a little while before you start thing bracketology.

Ok, I know Stoichiometry can be tricky enough without adding an extra twist to it, but lets talk about limiting reactants. I know I know, you probably feel like our buddy Brick does but just here me out. Limiting reactants are elements or molecules that limit the amount of product that can be produced in a reaction. If that doesn’t quite make sense, let me explain it like this…

Lets say you are a luxury car manufacturer. Like, big time luxury. Like, handmade cars… leather, wood, gold trim, the works. And for the sake of argument, and this example, that at the end of production the last thing your company does is put the tires on the finished car bodies. Now the end of production would follow this reaction:

4 Tires    + Body → Car

→

So if I had 16 tires and 4 car bodies I could make…

ta-da, 4 cars.

BUT! What if my tire supplies were running low and I only had 8 tires and 4 car bodies. How many cars could I make then?

I could only make 2 cars!

The amount of tires I had, limits the amount of cars I can produce (important word). Therefore, my tires are my limiting reactant! Because they limit the amount I can produce.

Now, lets apply that same concept to a chemical reaction, using what we have learned about Stoichiometry and it should be no sweat! First, we need a balanced chemical reaction. Then we need a given. Lets do the first example from our Limiting reactants packet as our reaction.

So, if you notice, we have 2 givens. These would be the amounts we put together in a reaction… BUT! we have to figure out which one is the limiting reactant! So, first lets assume O2 is the LR and see how much product (CO2) we can produce…

So we’ll put our new information into the chart to keep track of our data. It would look something like this…

Now lets assume CS₂ is the LR and see how much product (CO₂) we can produce…

Now our chart will look something like this…

In conclusion the reactant that produces the least amount of product is the 5.55 moles of O₂! It only produced 1.85 moles of CO₂, while 2.45 moles of CS₂ produces 2.45 moles!
So O₂ is our Limiting reactant and CS₂ is our Excess Reactant!

Now, there are some further steps you’ll have to do in the packet (how much Excess Reactant was used, what amount is leftover, what are the moles of the other product) and you may have a given in grams that you’ll have to convert… but all these are things you have done before. When in doubt, read the question carefully. There are key words that will help you determine your given and what you are solving for! Good Luck!

c/o P. Troy (2nd Period)

Limiting Reagents

This is how you feel when you find out you’ll be grading your own Stoichiometry Quiz

Today we’ll be receiving our quiz grades… but more important than me grading them and handing them back, is you checking them and understanding what was right or wrong. So we’ll be grading our own quizzes today. The answers are posted on the Docs page, or by using the link below.

Stoichiometry Quiz Answers

We’ll also be starting our large packet on Limiting Reactants today. It too is posted on the Docs page.

You would really have to be a Simpson’s fan to get that reference…

Regardless, to get everyone back on track after the wacky week last week, we’ll be in the lab today doing one of Mr. Fogel’s favorite labs… the Gold & Silver Penny Lab!

We’ll be back on topic tomorrow discussing Limiting Reactants. More info to come!

The link to the quiz I gave the first three classes (and the one Mr. Fogel gave his classes) is to a quiz with a mistake on it. The mistake has been corrected (on this site) and the link is now to the correct version of the test. I’ll tweet this info as well. Sorry for the confusion.